The engines of boats having a water-cooled engine as part of the drive system are cooled by drawing and circulating water obtained from the waterway during operation of the boat. When a boat having a water cooled drive system is used in shallow waterways, shallow marshes, or swamps, obstructions including floating and underwater vegetation, tree limbs, branches, roots, mud bottoms, rocks, and reefs are likely to be encountered. These obstructions may prevent the circulation of water from the waterway making the engines of such boats prone to overheating. When a boat having a water-cooled engine as part of the drive system is operated in an extremely shallow waterway that consists mainly of a slurry of water, vegetation, mud, sand and other debris, such waterway is often unsuitable for providing circulating water for cooling the engine.
Some boats incorporate engine cooling systems, called keel cool systems that have heat exchangers that extend from the bottom of the boat hull surfaces or that are placed in recesses on the bottom of the boat hull. Such keel cool systems are unsuitable for cooling a boat engine when the boat is operated in extremely shallow water environments due to the risk of damage to the boat hull and the cooling system caused when the boat strikes or engages the water bottom and because mud and other debris in the water environment will coat or become lodged around the heat exchangers and reduce their effectiveness in cooling the engine of the drive system.
Many boats have a drive assembly that incorporate fins and cavitation plates around the propeller in order to retain and maintain water slurry around the spinning propeller to prevent incidences of ventilation and cavitation and the loss propeller thrust. However, when boats utilizing such orienting fins and cavitation plates are operated in a shallow water environment where a slurry of water, mud, sand and other debris is present, such operation often results in damage to the drive shafts, bearings, seals and bushings contained in the drive assembly of the boat. This will lead to breakdowns and the cost and inconvenience of retrieval of the boat from a remote location along with associated costly boat repairs.
Some boats have a drive assembly with a skeg that extends downward from the bottom of the boat hull or from an elongated rudder or drive shaft. The lower surfaces of such skegs generally are angled at intersecting straight lines or the lower surfaces of such skegs are angled on intersecting straight line surfaces and corresponding curve surfaces. Such skeg shapes are generally unsuitable for shallow water environments. Such skeg shapes are more likely to engage and contact the water bottom or other obstructions and damaged because their shapes do not allow for a smooth or consistent transition over obstacles encountered in the waterway as the boat is propelled.
Some boats have a drive assembly with an extending drive shaft that pivots both up and down and right and left for steering the boats. The pivot assemblies on such a drive assembly provide a weak link in the assembly and are easily damaged when obstructions are encountered.
Consequently, there is a need for a boat for use in shallow water environments having an improved drive system for that will minimize or eliminate the risk of drive system damage caused by waterway obstructions.